It will depend on the architecture you used to build the software. If you have a server application, which provides connection to customers via Socks or WCF, then this is the way. Use the same layer architecture to send the information (Socks, wpf, remoting or other)
Now, if your client applications connect to the database directly, the solution could be to create a table and take the update from time to time. You could leave a thread running isolated on the client, checking for changes. This would avoid the construction of an exclusive server application for this purpose
The json case would only advise for web applications. If your application is web-based take a look at this Html5 resource.
http://www.w3schools.com/html/html5_serversentevents.asp
I didn’t understand it very well. You want to know which is the best option, out of the three?
– Randrade
Yes, or any other suggestion. @Renilsonandrade
– Lucio Rubens
I believe that solutions 2 and 3 are the easiest to do (at least in my view)
– PauloHDSousa
The performatic would look something like this: https://msdn.microsoft.com/en-us/library/ms973857.aspx
– Leonel Sanches da Silva